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8252399: Update mapMulti documentation to use type test pattern instead of instanceof once JEP 375 exits preview
Reviewed-by: dfuchs, psandoz, smarks
1 parent 0f2402d commit fbe40e8

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src/java.base/share/classes/java/util/stream/Stream.java

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Original file line numberDiff line numberDiff line change
@@ -340,6 +340,8 @@ public interface Stream<T> extends BaseStream<T, Stream<T>> {
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*/
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DoubleStream flatMapToDouble(Function<? super T, ? extends DoubleStream> mapper);
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// THE EXAMPLES USED IN THE JAVADOC MUST BE IN SYNC WITH THEIR CORRESPONDING
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// TEST IN test/jdk/java/util/stream/examples/JavadocExamples.java.
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/**
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* Returns a stream consisting of the results of replacing each element of
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* this stream with multiple elements, specifically zero or more elements.
@@ -386,8 +388,8 @@ public interface Stream<T> extends BaseStream<T, Stream<T>> {
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* <pre>{@code
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* Stream<Number> numbers = ... ;
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* List<Integer> integers = numbers.<Integer>mapMulti((number, consumer) -> {
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* if (number instanceof Integer)
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* consumer.accept((Integer) number);
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* if (number instanceof Integer i)
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* consumer.accept(i);
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* })
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* .collect(Collectors.toList());
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* }</pre>
@@ -397,8 +399,8 @@ public interface Stream<T> extends BaseStream<T, Stream<T>> {
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* <pre>{@code
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* class C {
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* static void expandIterable(Object e, Consumer<Object> c) {
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* if (e instanceof Iterable) {
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* for (Object ie: (Iterable<?>) e) {
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* if (e instanceof Iterable<?> elements) {
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* for (Object ie : elements) {
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* expandIterable(ie, c);
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* }
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* } else if (e != null) {
@@ -407,8 +409,8 @@ public interface Stream<T> extends BaseStream<T, Stream<T>> {
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* }
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*
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* public static void main(String[] args) {
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* Stream<Object> stream = ...;
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* Stream<Object> expandedStream = stream.mapMulti(C::expandIterable);
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* var nestedList = List.of(1, List.of(2, List.of(3, 4)), 5);
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* Stream<Object> expandedStream = nestedList.stream().mapMulti(C::expandIterable);
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* }
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* }
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* }</pre>
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,72 @@
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/*
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* Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import org.testng.annotations.Test;
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import java.util.List;
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import java.util.function.Consumer;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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import static org.testng.Assert.assertEquals;
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/*
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* THE CONTENTS OF THIS FILE HAVE TO BE IN SYNC WITH THE EXAMPLES USED IN THE JAVADOC.
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*
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* @test
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* @run testng/othervm JavadocExamples
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* @summary Checks to ensure example code displayed in the API documentation of
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* java/util/Stream compiles correctly.
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*/
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public class JavadocExamples {
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// From mapMulti
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@Test
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public void testNumberIntegerExample() {
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Stream<Number> numbers = Stream.of(1, 2, 3.0);
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List<Integer> integers = numbers.<Integer>mapMulti((number, consumer) -> {
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if (number instanceof Integer i)
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consumer.accept(i);
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})
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.collect(Collectors.toList());
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assertEquals(integers, List.of(1,2));
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}
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@Test
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public void testExpandIterableExample() {
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var nestedList = List.of(1, List.of(2, List.of(3, 4)), 5);
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Stream<Object> expandedStream = nestedList.stream().mapMulti(C::expandIterable);
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assertEquals(expandedStream.toList(), List.of(1,2,3,4,5));
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}
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static class C {
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static void expandIterable(Object e, Consumer<Object> c) {
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if (e instanceof Iterable<?> elements) {
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for (Object ie : elements) {
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expandIterable(ie, c);
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}
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} else if (e != null) {
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c.accept(e);
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}
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}
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}
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}

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